1. Field of the Invention
The present invention relates generally to color display devices and, more particularly, to a color micro-mirror projector.
2. Discussion of Related Art
Micro-mirror projectors are also called digital light processing (DLP) projection devices. Micro-mirror projectors have been developed by Texas Instruments, and a typical micro-mirror projector adopts digital micro-mirror devices (DMDs) to control light beams to enter the display light path. A typical DMD includes a plurality of supporting posts, a plurality of torsion hinges, and a plurality of micro-mirrors formed on a semiconductor substrate thereof. The semiconductor substrate can be, e.g., a silicon substrate. Each torsion hinge is positioned between two adjacent supporting posts, and each micro-mirror is installed on a given torsion hinge. When controlling signals are input to the DMD, the micro-mirrors would rotate around the corresponding torsion hinges.
Referring to FIG. 3, a conventional micro-mirror projector 1 includes a light source 10, a converging lens 20, a color wheel 30, a shaping lens 40, a micro-mirror chip 50 and a projection member 70. The color wheel 30 has at least red, green and blue segments. The micro-mirror chip 50 has a plurality of digital micro-mirror members 51 and a processor 52 formed thereon. Each micro-mirror member 51 has a plurality of micro-mirror (not shown) formed thereon. The light source 10 is used to emit a light beam. The converging lens 20 is used to converge the light beam to the color wheel 30. The color wheel 30 is disc-shaped and rapidly rotates across the converged light beam to generate red, green and blue lights. The shaping lens 40 is used to shape the red, green and blue lights as parallel lights and transmit the parallel lights to a corresponding micro-mirror member 51 of the micro-mirror chip 50. The micro-mirror member 51 receives a controlling signal from the processor 52. Upon receipt of an appropriate signal, the micro-mirrors thereon rapidly rotate and respectively transmit the corresponding parallel lights to the projection member 70, at a given/selected time. The projection member 70 is used to transmit the received lights onto a projection screen 80. Therefore, an image is displayed on the projection screen 80.
However, each pixel on the projection screen 80 is in accordance with the corresponding micro-mirror. When the projection screen 80 is relatively big, energy loss of the lights transmitted onto the projection screen 80 is relatively large. Therefore, divisions between adjacent pixels are relatively clear (i.e., well-defined). This results in the image being unsatisfactory.
What is needed, therefore, is a micro-mirror projector that can provide better images on the projection screen.